This Learning Web unit from the US Geological Survey offers an engaging, interdisciplinary exploration of caves for grades K-3. Although Exploring Caves is listed as a life science unit, it encompasses a wide range of fields: earth science, hydrology, mapping, biology, and anthropology. The unit is linked by an original read-aloud story about the adventures of two kids who get lost in a cave and are helped out by a talking bat (why not?). Each chapter comes with a set of lessons and activities "designed to stimulate thinking and new ways of looking at the world."